<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/jquery.js"></script>
</head>
<body>
    <button>按钮</button>
    <button>按钮</button>
    <button>按钮</button>
    <button>按钮</button>
    <script>
     $(function() {
        //  $("button").click(function() {
        //      $(this).css("background","red").siblings("button").css("background","");
          
        //  })
        $("button").click(function() {
           $(this).siblings("button").css("background","red")
        })
       
     })
    </script>
</body>
</html>